From Zero to 30,000 Deals: How Continuous Testing Enabled SumUp's Field Sales Success

For little over a year we had the opportunity to work on a greenfield project for SumUp, dubbed “Field Sales Sidekick”. Since launch that app processed 30,000+ field sales deals, withstood 6x team growth and rolled out in 8 countries, with the remaining SumUp markets on the up-next-list.

SumUp set the ambitious goal to 10x their field sales efforts in the first 12 months and to reach feature parity with similar app being used by their competition.

And we’re happy to announce that most of those goals could be met 🎉.

This post unpacks how quick iterations, a trusting, integrated team and tightly integrated research and design could make all that happen.

If you want to get to the juicy part right away, please feel free to:

The challenge Link to this headline

The order was a pretty tall one:

• Design and build the first version of the app in 4 weeks — we need people to get excited about this and understand that talking time is over (the idea for the app being discussed internally for several month already)
• Integrate the app with our internal infrastructure to leverage existing processes and to ensure smooth collaboration between back-office teams and field sales agents
• Work with our existing design language to make the app look and feel like SumUp
• Enable localization of the app so field sales agents can work in their native language
• App architecture must allow for feature flags per market and should be flexible enough to eventually support all markets SumUp is active in — including overseas like US and Brazil
• Iterate quickly and make sure that each feature release make the app noticeably more useful for all user groups: field sales agents, sales managers, back-office support

SumUp hired us for the job because they knew that all this could only be achieved through careful UX research, usability testing and integrated design and development — all out the hands of a small, hands-on team.

Our approach: 2 week sprints and full, hot-potato-style team integration Link to this headline

We rejected the traditional siloed team structure in favor of constant collaboration—everyone sharing responsibility for the user experience through rapid cycles of prototyping, testing, and refining together. Instead of lengthy requirements and Jira bureaucracy, we built shared understanding by tossing ideas back and forth like a hot potato until we got it right.

This only works when management has the courage to trust their team to shape the roadmap:

To leave it to a broader group in your team to jointly decide your roadmap... that shows you trust your team to do the right thing.

It requires everyone to check their ego at the door, embrace psychological safety where failed experiments become data rather than disasters, and accept that the person closest to the problem—whether that's a field sales agent or a junior developer—often has the best solution.

Behind the Scenes - Managing Complexity Link to this headline

Now, imagine aligning stakeholders across field sellers, managers, VPs, sales ops, revenue ops, talent teams, and sales enablement—each group with distinct priorities—while spanning UK, Europe, Brazil, and Latin America markets. Add 10+ years of legacy systems into the mix, and you've got a fascinating puzzle to solve. We learned that success meant finding the sweet spot where user needs and business requirements genuinely converge, rather than trying to accommodate every request that came our way.

Key Breakthrough Moments Link to this headline

Our continuous testing cycles revealed insights we never would have caught in requirements documents—like when field sellers consistently struggled to find commission details across multiple screens, leading us to create a unified transparency feature that became the product's cornerstone. Alina's field shadowing confirmed what our usability sessions kept showing: sellers were drowning in tool complexity when they should be focused on selling ("It's frightening to be a field seller," she reported back). The inventory management feature perfectly illustrates how testing shaped our roadmap—what started as a minor enhancement kept surfacing in user feedback until we realized it was actually solving hours of weekly frustration, transforming it from nice-to-have to must-have.

The Results That Matter Link to this headline

Let’s talk about results. In roughly a year we managed to accomplish the following things:

• 30,000 deals closed through Sidekick
• 6x growth in field sales team size
• 8+ countries in international rollout
• Feature parity with solutions competitors use — only that Sidekick is fully integrated with SumUp’s systems

All this started out to be the app to support specifically field sellers but the app is gaining traction inside the organization.

Other sales teams with similar processes are interested in the solution and are already in the process of migrating their workflows from other, third party solutions into Sidekick; making Sidekick a critical tool in the sales toolchain throughout.

The Case Study Link to this headline

We recorded all this and more with details about outcomes over here in the project case study for SumUp Sidekick: